In many parts of the world, especially the arid and semi-arid regions, with scarce animal feed resources, low quality non-conventional feeds are frequently fed to livestock (Mahgoaub et al., 2008). High salinity of irrigation water and agricultural soil is a major impediment to the cultivation of traditional fodder crops as well as high costs of transporting feed to the Sinai Peninsula. Reducing feed costs and/or increase feed utilization may be an effective key for increasing the profitability and sustainability in these areas. Several studies recommended cultivating salt and drought tolerant fodder shrubs (e.g. Atriplex spp.) and salt and drought tolerant grasses and legumes such as Pearl millet which might fill the gap in animal feeding production in arid and saline areas (Hanafy et al., 2007 and El-Shaer, 2010). However, high salt content of halophytes is perhaps the major negative component when they are used as sole diets. Therefore, appropriate mixing of grass with shrubs has been assumed as an effective method of diluting the adverse effects of unlike secondary compounds especially, tannins (Bhat et al., 2013). Several feed supplements have been used to improve animal performance either by manipulation of the rumen environment or by directly altering the composition and metabolic activities of rumen microorganisms (Azzaz et al., 2015a). Microorganisms frequently used as microbial feed additives/direct-fed microbial (Yoon and Stern 1995; Walker 2007 and Seo et al., 2010). Propionibacteria (Propionibacterium freudenreichii) as additives are capable of utilizing lactic acid and promoting the production of propionate in the rumen (Nisbet and Martin 1994; Kung and Hession 1995).These bacteria represent 1.4% of rumen total microbial population and propionate which is produced is considered a major precursor for glucose production through gluconeogenesis, sparesglucogenic amino acids in hepatic gluconeogenesis, inhibits hepatic lipid oxidation and work as antiketogenic agent (Morsy et al., 2014). Other researches reported that direct-fed microbial supplementation such as propionibacteria may increase the molar propionate and reduce rumen acidosis and increase hepatic gluconeogenesis and increase weight gain when fed to ruminants (Kim et al., 2000; Ghorbani et al., 2002 and Stein et al., 2006). Moreover, microbial feed supplementation has improved milk yield, milk composition, feed efficiency and animal's health (Kholif et al., 2000 and Raeth-Knight et al., 2007). However, Morsy et al. (2014) found that supplementing dairy buffalo’s rations with propionibacterium strain P169 did not affect nutrients digestibility, milk yield or milk components. Also, Raeth-Knigh et al. (2007) did not observe any differences in ruminal pH, volatile fatty acids (VFA) concentrations and nutrients digestibility of mid-lactation cows fed diets supplemented with Lactobacillus and propionibacteria strains. The objective of this study was to examine the effects of feeding cultivated salt-tolerant plants mixture contained of 25% A. nummularia and 25% P. glaucum with Propionibacterium freudenreichii on productive performance of Barki ewes under saline conditions.
MATERIALS AND METHODS
This study was carried out in South Sinai research Station (Ras Sudr), located at South Sinai Peninsula, belonging to Desert Research Center, Ministry of Agriculture and Land Reclamation as a part of Bilateral Project (ICBA-DRC) in Egyptin with Dairy Sciences Department, National Research Centre, Giza, Egypt. Two cultivated salt-tolerant forages; old man saltbush (Atriplex nummularia L.) and pearl millet (Pennisetum glaucum L.) were collected from the Farm of South Sinai Research Station.
Animals and treatments:
Thirty-three Barki ewes an averaged (43.38±0.61kg) body weight were randomly distributed into three equal groups (11 ewes each). Each group was housed in separated shaded mating pen. Ewes of the first group were fed a control diet contained berseem hay and CFM (50:50% as DM basis) (control group); the second group fed ad libitumon mixture contained 25% A. nummularia and 25% P. glaucum with 50% CFM (G1). The third group was fed ad libitum on mixture contained 25% A. nummularia and 25% P. glaucum with CFM (50%) +1gm P169 (G2). Propionibacteria (P169) was mixed with small amount of CFM and additives once daily at the time of feeding. The CFM consisted of 32% undecorticated cotton seed cake, 27% yellow corn, 30% wheat bran, 5% linseed meal, 3% molasses, 2% limestone and 1% sodium chloride. The whole ration was given to cover energy maintenance and production requirements of ewes according to the nutritional requirements of Kearl (1982). Table (1) shows the chemical composition of experimental diets offered to ewes of control, G1 and G2 which was determined according to AOAC (2007).
The Propionibacteria freudenreichii strain 169 (Dairy ProP169®) is a dried material of viable bacteria prepared by Bio- Vet Inc. USA., contains a live bacteria count: 30 Billion (3 x 1010) colony forming units (CFU)/ minimum per gram). The additives were sealed into 2 kg packages by the manufacturer and kept frozen at−20° C as recommended until feeding. Live bacterial numbers of product were enumerated with species specificity for genus P. freudenreichii. They have been used as direct- fed microbial (DFM) package was analyzed for total counts of propionibacteria according to Vedamuthu and Reinbold (1967).
The animals of each group were fed and housed in a semi-closed pen, roofed with and walled in four directions with concrete. Both of berseem hay, dried chopped mixture and CFM were weighed and offered at 9 a.m.; refusals were daily collected and weighed for each group of animals to estimate the actual feed intake. Fresh water was available twice daily. Feed allowances were adjusted every month according to body weight and milk yield according to Kearl (1982). All animals were weighed monthly in the morning before supplementing feed and after fasting period about 12 hours. The offsprings were individually weighed at birth and then weekly until early weaned (80 day). All new lambs were fed on barley after the first month of age even weaning. Milk yield was determined biweekly from lambing up to 12 weeks lactation period, representing early (2nd & 4th week), mid (6th & 8th week) and late lactation periods (10th & 12th week), through the complete hand milking after fasting of lambs for 12 hours for two consecutive days one at night and the next at morning to cover 24 hours (Abdalla et al., 2007). Representative milk samples were taken from 6 animals of each group for chemical composition analysis.
Four rams of each group with an average live weight (45.58±1.43kg) were individually kept and fed in metabolic cages to determine digestibility coefficients, feeding value and N balance. The digestibility trial was extended for 21 days as a preliminary period followed by 7 days as a collection period. All rams were fed on the same diets groups used with lactating ewes to cover 50% TDN maintenance requirements of rams according to Kearl (1982). Feed intake and residuals were daily weighed and recorded during the collection periods, Total daily faces output was collected and 10% sample was taken and kept for later analysis. Faces and feeds were first dried at 65º C for 48 hours and final dried were determined after drying in a forced air oven at 105º C for 3 hours. Dried samples were mixed and ground to pass through a 1.0 mm mesh screen for chemical composition. Total daily urinary excreted from each rams was collected in jar containing 100 ml of 10% H2SO4 and 10% sample was taken and kept for later analysis. Samples of rumen liquid were taken 3 hrs after feeding to estimate rumen pH, ammonia and volatile fatty acids concentrations.
Dry matter (DM), crude protein (CP), crude fiber (CF), ether extracts (EE) and ash of feed ingredients and feces were determined according to AOAC (2007), while carbohydrates as nitrogen-free extract (NFE) was calculated by differences. Cell wall constituents of feed ingredients as neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined according to Van Soest (1991). Gross energy (GE) of feed and feces was measured by bomb calorimeter (IKA, model C 200, Staufen, Ger- many), using benzoic acid as standard. The pH value of rumen fluid samples was determined using pH meter. Total volatile fatty acids and ammonia nitrogen were determined according to Warner (1964). Milk samples were analyzed for total solids, fat, protein and lactose using infrared spectrophotometry (Foss 120 Milk Scan, Foss Electric, Hillerod, Denmark) according to AOAC (2007). The ash content of milk was determined after heating in muffle furnace at 550C for 16 hour and solid not fat content was calculated by differences. Fat corrected milk (4% fat) was calculated by using the following equation according to Azzaz et al. (2013):
4 FCM (%) = 0.4 Milk yield +15 Fat yield.
Data collected for digestibility trial were subjected to statistical analysis as one-way analysis of variance using SAS (2004) according to the following model: Yij = μ + Ti + eij.
Where: Yij = the observation μ= overall mean
Ti= effect of treatment eij= experimental error
While, Data collected for milk composition were analyzed statistically according to the following model: Yij= μ +Si+Tj + (ST) ij + eijk.
Where: Yij= the observation μ= overall mean
Si= effect of sampling period Ti= effect of treatment
(ST) ij= effect of interaction between sampling period and treatment and eij= error
The significant differences between means of studied groups were tested according to Duncan's New Multiple Ranges Test (Duncan, 1955).
RESULTS AND DISCUSSION
The chemical compositions result of berseem hay, Atriplex nummularia, Pennisetum glaucum and halophytes mixture are summarized in Table 1. The results revealed that there are wide variations in chemical compositions of the investigated forages. Halophytes mixture was having relatively high values in DM, CF, EE, NFE, GE and ash content, but it was has low values of OM, CP, NDF and ADF compared to berseem hay. The results are in agreement with previous reports executed on saline tolerant plant mixtures (Fayed et al., 2010 and Helal et al., 2017).
Digestibility coefficients and nutritive values:
Dry matter intake (DMI), digestibility coefficients and nutritive values results are presented in Table 2. The DMI was insignificantly increased for halophytes mixture group or halophytes plus probiotic of strain P169 group compared to group fed the control diet. This results are in agrees with those reported for halophytes mixture by El-Shaer (1995, 2002), or supplementing of propionibacteria P169 which reported by Ghorbani et al. (2002), Raeth-Knigh et al. (2007), Thompson (2011), West and Bernard (2011), Ebeid et al. (2013) and Morsy et al. (2014). In contrast, Helal et al. (2018) found that DMI (g/KgW0.75/d) was higher for sheep fed berseem hay vs. halophytes mixture.
Digestibility coefficients of DM, OM, NDF, ADF and DE were significantly increased with control group compared to other tested groups as shown in Table 2. However, digestibility of CP showed improvement (P<0.05) for rams fed halophytes mixture plus probiotic of strain P169 compared with control group. These finding in consistent with the results reported by Helal et al. (2018). The lowering nutrients digestibility of halophytes mixture compared to alfalfa may be attributed to higher content of ash and saponin in A. nummularia (Hassan 2009 and Fayed et al., 2010). On the contrary, previous studies showed that addition of propionibacterium strain P169 improved all nutrients digestibility (Lehloenya et al., 2008a, Boyd 2009 and Azzaz et al., 2015); however, it didn’t has significant effects in other studies (Ebeid et al., 2012 and 2013).
Nutritive values expressed as TDN and DCP% are shown in Table 2. Total digestible nutrients (TDN%) showed higher (P≤0.05) improvements for rams fed P169 (G2) than those fed without any additives (G1) while the highest values were detected for control group. However, Rams fed P169 group had lower (P≤0.01) in DCP% compared to group fed the control diet. These results are in the same trend with those found by Helal et al (2017) who found that Shami goats fed Salt-tolerant plants mixture had lower (P<0.05) values of DCP and TDN% than those fed the control group. Also, Morsy et al. (2014) who reported that TDN% was higher (P≤0.05) with the control group than experimental additives. On the other hand, no significant differences in DCP% were observed between treatments (Ebeid et al., 2013; Morsy et al., 2014 and Azzaz et al., 2015).
Results of nitrogen utilization (g/KgW0.75) for three experimental groups are offered in Table 3. Nitrogen utilization was affected significantly by direct-fed microbial supplementation between all experimental groups. Nitrogen intake showed a significant increase (P<0.01) in control group followed by (G2) while the lowest was recorded for (G1). Higher nitrogen intake may due to high content of crude protein in berseem hay vs. halophytes mixture (Table 1). Nitrogen in urine was significantly higher (P≤0.05) for rams fed berseem hay vs. G1 and G2 but no significant differences of nitrogen in feces and nitrogen balance% of nitrogen intake were observed among all experimental groups. However, rams fed control diet and diet supplemented with P169 (G2) had highest (P≤0.05) digested nitrogen vs. G1. At similar trend, nitrogen balance recorded the highest (P≤0.05) values for rams fed control diet followed by P169 (G2) Then G1 (0.08, 0.07 and 0.06 g/KgW0.75, respectively). This may be due to higher CP content and its digestibility in alfalfa. The results are similar with those reported for halophytes mixture by El-Shaer et al. (2001) and Helal et al. (2017), or supplementing of propionibacteria P169 which reported by Lehloenya et al. (2008a) and Ebeid et al. (2013).
Some rumen liquor parameters are shown in Table 4. There were no significant differences among tested groups in pH, NH3-N and TVFA´s values. It was noticed that rams fed propionibacteria P169 (G2) recorded the lowest values of pH versus those fed in control diet. Similar results were obtained by Ebeid et al. (2013) and Narvaez et al. (2014). Rams fed G2 had higher values of NH3-N concentration than those fed G1, while the highest values were observed for control group. This is may be due to high content of CP in berseem hay. At the same trend, TVFA´s concentration showed the highest values for control group followed by G2 and G1 with no significant difference between them. This finding may be attributed to higher salt and lower energy contents of atriplex which shorting the rumen turnover time with subsequent influences on rumen physiology and metabolism (Konig 1993 and Fayed et al., 2010).
Milk yield and composition:
Milk production and milk composition data are illustrated in Table 5. Average milk yield and 4% Fat-corrected milk (FCM) were slightly insignificant increased in control group compared to G1 and G2. Similar results in Shami female goats on salt-tolerant plants obtained by Abdalla et al. (2013) or supplementing of propionibacteria P169 which reported by Mandebvu et al. (2003) and Morsy et al. (2014). On the contrary, Ibrahim (2014) found that Barki ewes fed halophytic silage had higher (P<0.01) average daily milk yield (696.6 ml) than ewes fed berseem hay (683.3 ml). Moreover, milk yield was higher significantly for animals fed P169 than those of control (De Ondarza and Seymour 2008 and Azzaz et al., 2015b). Overall mean percentages of total solids (TS), solid not fat (SNF) and ash content were significantly (p<0.05) higher for Barki ewes fed G2 diet than other groups. Also, late stage of lactation showed the highest (p<0.05) values of fat, TS and SNF compared with other stages but there were no significant differences among all groups in lactose and total protein. The results were in agreement with Ibrahim (2014) who found that percentages of milk fat, lactose, TS, SNF and ash content were higher for ewes fed halophytic silage than those fed berseem hay, which is probably due to an increase of salt in the silage halophytes. Also, studying on buffaloes fed yeast or P169+yeast; Azzaz et al. (2015b) stated that milk fat, TS and SNF were higher for yeast culture or yeast+P169 than control treatment. However, Morsy et al. (2014) found that supplementing dairy buffalo’s rations with P169 did not affect milk yield or milk components. The improvement of milk yields and components by ewes supplemented P169 may be attributed to higher nutrients digestibility and improved rumen environmental conditions (Titi and Lubbadeh 2004 and West and Bernard 2011).
Live body weight changes:
Data of body weight changes by Barki ewes are presented in Table 6. There is no significant difference in initial and final body weight between experimental groups either before or after lambing. Similar results on ewes fed halophytic were obtained by Ibrahim (2014) and Helal et al. (2017, 2018) or supplementing of propionibacteria P169 which reported by Narvaez et al. (2014). These results demonstrated the potentiality of such halophytes mixture to fulfill the animal requirements to maintain their body weight. From another point of view, this slight increase in final body weight might be due to the increase in extracellular fluid in G2 as reported by (Shawkat et al., 1988; El-Shaer 1996; Abou El-Nasr 1998 and Shaker et al., 2014).
Feed intake and economic efficiency:
Dry matter intake and feed efficiency by ewes are shown in Table 7. Data revealed that total dry matter intake (g/h/d) were very similar, being 1580, 1550 and 1570 for ewes fed control, G1 and G2, respectively. The corresponding daily TDN and DCP intakes also very similar, being 875, 825 and 830 g TDN and 146, 120 and 123 g DCP. The lowest total feed cost along the feeding period was observed for animals fed halophytes mixture (G1 and G2) vs. those fed control group (6.41, 3.74 and 3.75 L.E, respectively). Economic efficiency (price of kg milk/cost kg total of consumed feed) showed the highest for ewes fed G2 (5.02) followed by G1 (4.98) compared to control group (2.96). The same trend was noted for the improvement% since the values were 169.59, 168.24 and 100, respectively. These results are supported by Swinney-Floyd et al. (1999) found improved feed efficiency in feedlot steers feed a wheat and corn-based diet supplemented with P. feudenreichii P63. Previous studies showed lower feed cost by sheep and goats fed rations of tree legumes than the control (Mehrez et al., 2011 and Helal et al., 2018a). In contrast, Huck et al. (2000) reported that feeding Propionibacterium freudenreichii to finishing heifers fed a corn-based diet did not have any effect on feed efficiency compared with controls.
Data of body weights of the lambs from birth to weaning are presented in Table 8. The findings of the present study showed an increase (p<0.05) in average daily gain for control group followed by G2 and G1 (0.177, 0.169 and 0.161, respectively) with no significant differences between them in birth weight and weaning weight. These results are in agreement with Mohammady et al. (2014) who found that no significant differences on birth weight, weaning weight and average daily gain by ewes fed on halophytic silage and berseem hay as basal diet. However, previous findings showed a higher average daily gain for animals fed P169 than those of the control (McPeake et al., 2002; Krehbiel et al., 2003 and Adams et al., 2008). The slight differences in performance of ewes fed halophytes mixture and berseem hay as a conventional diet, it could be due to the higher metabolic energy and protein content (EL-Shaer 1981 and Ibrahim 2002).
Data of the reproductive performance of Barki ewes fed halophytes mixture with propionibacteria P169 are shown in Table 9. The obtained results revelated that conception rate was similar for ewes fed G1 and G2 (90%) while it was 100% in control group but the differences were not significant. These results are agreed with those reported by Mohammady et al. (2014) for the same breed. However, lambing rate showed higher for ewes fed G1 and G2 (100%) in comparison with control group (90%), while total number of offspring was similar between all groups with no mortality cases were found in the current experimental till weaning. Ewes fed halophytes mixture plus probiotic of strain P169 did not show negative effects on reproductive performance.
The current study revealed that Barki ewes fed halophytes mixture with Propionibacterium freudenreichii strain P169 showed improvements of productive performance, economic efficiency and decrease feed cost with no deleterious effects on their health under South Sinai conditions.
This article was originally published in Research Journal of Animal and Veterinary Sciences, 10(2): pages: 18-27. DOI: 10.22587/rjavs.2018.10.2.3. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.